Sheet metal bending tool



Feb. 21, 1961 s w KROLICK 2,972,270

SHEET METAL BENDING TOOL Filed Jan. 26, 1959 INVENTOR. STANLEY W/IROLICK Y iZAMQ j SHEET METAL BENDING TOOL Stanley W. Krolick, 995 W. 5thSt., Livermore, Calif.

Filed Jan. 26, 1959, Ser. No. 789,041

2 Claims. (Cl. 81-15) This invention generally relates to hand operatedtools for bending sheet metal or the like, and is more particularlydirected towards such a tool for producing so-called government orpocket locks on sheet metal duct work.

In the fabrication of sheet metal ducts, the workman is required toprovide interconnected flanges at numerous locations, such as at pointsof juncture, and in this connection, government or pocket locks arefrequently specified. As is well known to those in the art, these locksare usually formed by manually beating with a hammer one of a pair offlanges to form an angle of about 45 degrees relative to the otherflange, and then utilizing a hand grip tool to forcibly bring the twoflanges into immediate adjacent relationship. The hand grip toolspresently available are not satisfactory from a number of viewpoints,requiring excessive effort on the part of the operator. Also, in manyinstances, such as in the case of overhead duct work, such tools cannotbe properly utilized at all.

It is therefore an object of the present invention to provide a sheetmetal bending tool which is arranged to give maximum mechanicaladvantage to the user and in which the jaws are mounted in a novelmanner to expedite the use of the tool.

Another object of this invention is to provide a tool utilizing a pairof jaw elements selectively movable from and towards each other and inwhich the jaws are arranged for movement about pivots which result inthe normally planar opposed surfaces of the jaws, being disposed inparallel adjacent relationship when the jaws are closed and in angularrelated relationship when the jaws are open.

A further object of the invention is to provide a tool as hereinabovedescribed in which the jaw elements are mounted on a pair of cooperatingmanually engageable handles extending for a substantial distance, and inwhich each of the jaws consists of a planar element whose longitudinalaxis is offset from the normal transverse axis of the tool.

Yet another object of the invention is to provide a tool of thecharacter described in which the jaws open and shut relative tostationary corner portions thereof so as to facilitate their use andpermit ready engagement of the flanges being engaged thereby.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of the preferred form of the invention which is illustratedin the drawing accompanying and forming part of the specification. It isto be understood, however, that variations in the showing made by thesaid drawing and description may be adopted within the scope of theinvention as set forth in the claims.

Referring to said drawing:

Figure 1 is a side elevational view of the tool of the presentinvention.

Figure 2 is a top plan view thereof.

Figure 3 is an enlarged portional view similar to Figure 1 andillustrating the position of the parts when the jaws are in their openposition.

Staes Pa e 2,972,270 .gPatented Feb. 21,, 1961 Figure 4 is an endelevational view of the jaws in their open position.

Figure 5 is a transverse cross sectional viewtaken substantially in theplane indicated by line 5-5 of Figure 1.

Figure 6 is a portional perspective view of a government or pocket lockduring course of formation thereof.

As here illustrated, the tool of the present invention incorporates apair of jaw elements indicated at 6 and 7 respectively which are adaptedto be selectively opened and closed by means of a pair of pivotallyconnected handle elements 8 and 9. As is typical with most hand operatedclamping tools, when the handles are spread apart as illustrated inFigures 3 and 4 of the drawing, the jaws will likewise be disposed intheir open position. Conversely, by bringing the handles together asshown in Figure 1 of the drawing, the jaw elements 6 and '7 will bebrought into immediate adjacent relationship and thereby in a conditionto form the government lock on a pair of sheetmetal flanges or otherwiseapply pressure therebetween. In order to translate handle movement intocorresponding movement of the jawswith a maximum mechanical advantageresulting therefrom, the structure dis closed in the drawing andpresently to be described is preferably employed. As here illustrated,each of the handles comprises an axially extending element 12 and 13which may be of cylindrical or other desired cross sectionalconfiguration. The inner end of each of the elements is flattened anddeformed to define an acute angle with the axis of the element so as toprovide a pair of extensions 14 and 16 respectively. The extensions 14and 16 are integral with their respective handle elements, and thedistal ends thereof are pivotally secured together such as by a pin 17or the like, such pivotal mounting permitting free movement of thehandle elements 12 and 13 from and towards each other.

Pivotally secured to the handles are a pair of arcuate flat links 21 and22, the links having ends thereof secured to the respective extensionsby pivot pins 23 and 24. It will be noted that the link 21, for example,has a first portion 26 of arcuate configuration with the radius ofcurvature being generated approximately from the other link pivot point24 and terminating ina reverse curve portion 27. The other link 22' isof similar configuration with its first arcuate portion 28 being curvedabout the pivot pin 23 and similarly provided with a reverse curvedportion 29. The links are likewise pivotally interconnected by a pin 30medially of their ends. The free ends of the links have secured theretoin a manner presently to be explained the jaw elements 6 and 7. However,irrespective of the shape or positioning of the jaws on the links, itwill be readily understood that as the handles are brought into adjacentrelationship from the position illustrated in Figure 3, the links 21 and22 will be moved until the ends of the curved portions 27 and 29 will bebrought towards each other and consequently effect a closing of thejaws. On the other hand, the jaws are opened through a contrary movementof the handle elements.

The shape and positioning of the jaws 6 and 7 on the respective linksconstitutes an important feature of the present invention. It will beseen that the jaws are each formed of a relatively planar block ofmaterial with the opposed confronting faces 31 and 32 being knurled, ifdesired, to provide a greater gripping action when the jaws are engagedwith the sheet metal or other object being clamped. It will also benoted from observing Figure 2 of the drawing that the longitudinal axisof each jaw defines an angle of about 24 degrees with the axes of thepivots 17, 23, 24 and 30, or with what might be termed a normaltransverse axis of the tool relative to the axes of the handle elements.It is also important to note that when the jaws are in their closedposition as shown in Figures 1 and 2, the jaws are disposed in paralleladjacent relationship relative to each other so as to permit thenecessary clamping action therebetween. However, when the jaws areoepned as shown in Figures 3 and 4, one corner of each of the jaws, dueto their positioning on the links and the nature of link movement willremain in immediately adjacent relationship as indicated at 36 with thejaws having their widest opening on the diagonally opposite corners 37and 38 of the respective jaws. Thus, when the handles are broughttogether, there is little or no movement of the jaw portions adjacentthe corner 36 and the other portions of the jaws are then broughttogether with the corners 37 and 38 having maximum movement towards eachother. In this manner, the jaws in their open position may be easilyplaced on the flanges to be secured or bent together and then bysqueezing the handles 8 and 9, may be gradually brought together toprovide the necessary deformation to the sheet metal. Also, by virtue ofthe angular disposition of the jaws relative to a longitudinal ortransverse axis of the tool, the entire unit may be used in otherwiseinaccessible locations, but without in any way sacrificing any of themechanical advantage arising from the link and extension arrangement.

A type of operation for which the tool has particular utility is in theformation of a government or pocket lock on sheet metal duct work. Asshown in Figure 6, such a lock is formed at the juncture between a pairof ducts 51 and 52. The end of the former is bent back on itself asshown at 53, then extends outwardly in an angularly disposed web 54 andterminates in a flange 56 parallel and spaced to portion 53. Duct 52 hasan end angular flange 57 disposed adjacent web 54 between flange 56 andportion 53. By bending flange 56 over flange 57, the lock is provided.

What is claimed is:

1. A sheet metal bending tool comprising a pair of handles, meanspivotally securing said handles together adjacent the ends thereof, apair of links with one of such links being pivotally attached to one ofsaid handles and the other of said links being pivotally attached to theother of said handles, means pivotally securing said links together,each of said linkshaving a jaw element operatively secured thereto, eachof said jaw elements comprising a generally rectangular block having alongitudinal axis offset from a transverse axis of said tool andlikewise defining an angle with the longitudinal axis of the tool, saidjaws having abutting corner portions normally positioned immediatelyadjacent each other during opening and closing of said handles, and saidjaws having corner portions at diagonally opposed positions relative tosaid adjacent portions having a maximum amount of movement from andtowards each other upon actuation of the handles.

2. Apparatus as set forth in claim 1 in which the opposed confrontingsurfaces of said jaws are substantially planar and positioned inimmediately adjacent relationship upon closing of said handles.

References Cited in the file of this patent UNITED STATES PATENTS791,245 Casterlin May 30, 1905 869,211 Mills Oct. 22, 1907 1,093,400Gottfrid Apr. 14, 1914 1,987,127 Rice Jan. 8, 1935 2,507,784 Hamel May16, 1950 FOREIGN PATENTS 926,929 Germany Apr. 25, 1955

